Each tire of an automobile has a nozzle for pumping in or leaking out the air therein in order to keep air pressure of the tire maintaining in a suitable range. At the beginning, air is pumped into the tire reaching a high level of air pressure for use. It is known that the air will leak out gradually. After a period of time, the air pressure is too low, so that the user must pump air into the tire again to reach the high level of air pressure.
There is no problem for the user to prevent the air pressure of the tire from reaching to over high pressure. That is, the user can easily adjust the tire pressure when pumping air into the tire. However, when air of the tire gradually leaks, it is difficult for the user to realize that whether the tire pressure is too low. It is dangerous that the user drives a car with tires of low pressure because the tires will cause too much heat when rolling on ground.
It is, therefore, an objective of the present invention to provide a valve for checking tire pressure which may obviate and mitigate the above-mentioned drawbacks.